Effects of calcium compounds on the carbothermic reduction of vanadium titanomagnetite concentrate (VTC) were investigated. It was found that calcium compounds had great effects on the metallization rate of the reduction product, the order of the metallization rate of reduction product being CaCO₃ > no additive > CaSO₄ > CaCl₂, which indicated that the addition of CaCO₃ was more conducive to promoting the reduction of iron than other calcium compounds. Gas analysis showed that there were mainly two processes in the carbothermic reduction of VTC, a solid-solid and a solid-gas reaction. The concentrations of CO and C0₂ were highest when CaC0₃ was added, while that in a roasting system decreased the most when CaCl₂ was added. X-ray diffraction (XRD) analysis showed that calcium compounds could change the reduction process of ilmenite in VTC. The phase compositions of the reduction products were changed from metallic iron (Fe) and anosovite (FeTi₂0₅) to metallic iron (Fe) and perovekite (CaTi0₃) when calcium compounds were added. Additionally, CaSO₄ and CaCl₂ could significantly promote the growth of metallic iron particles, though the existence of Fe-bearing Mg₂TiO₄ in reduction products was not conducive to the reduction of iron. The formation of FeS would further hinder the reduction of iron after adding CaSO₄.

中文翻译：

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钙化合物对钒钛磁铁矿精矿碳热还原的影响

研究了钙化合物对钒钛磁铁矿精矿（VTC）碳热还原的影响。发现钙化合物对还原产物的金属化速率有很大的影响，还原产物的金属化速率的顺序为CaCO ₃ >无添加剂> CaSO ₄ > CaCl ₂，这表明CaCO ₃的添加更多。比其他钙化合物有利于促进铁的还原。气体分析表明，VTC的碳热还原主要有两个过程：固-固和固​​-气反应。当CaCO ₃时，CO和CO ₂的浓度最高。添加CaCl ₂时，焙烧系统中的添加量下降最多。X射线衍射（XRD）分析表明，钙化合物可以改变钛白​​粉在VTC中的还原过程。当添加钙化合物时，还原产物的相组成从金属铁（Fe）和钙钛矿（FeTi ₂ 0 ₅）变为金属铁（Fe）和钙钛矿（CaTiO ₃）。此外，尽管存在含Fe的Mg ₂ TiO ₄，CaSO ₄和CaCl ₂可以显着促进金属铁颗粒的生长。还原产物不利于铁的还原。FeS的形成会进一步阻碍添加CaSO ₄后铁的还原。